Top police officials and activists from Boston and area communities blasted the state Senate Tuesday for watering down gun control legislation by stripping a provision aimed at keeping rifles and shotguns out of the hands of dangerous people.

“I’m real disappointed in the Senate,” said Boston police Commissioner William B. Evans, standing with more than a dozen police officials and gun control advocates at the State House.

“What the Senate chose to do is placate the NRA instead of supporting law enforcement,” said John Rosenthal, founder of Stop Handgun Violence.

The unusual public criticism
by police chiefs comes after the Senate last week voted to remove a House provision giving chiefs discretion to deny firearms identification cards, required to buy shotguns and rifles, to people they deem unsuitable. They now have that discretion over licenses to carry handguns.

“Are people really going to be any less dead if they’re killed with a rifle or a shotgun than a handgun?” Police Chief Terry Cunningham of Wellesley said at the morning press conference.

On Tuesday, both chambers named members to a conference committee on the legislation. The panel will have to act quickly to hammer out differences between House and Senate versions of the bill. Formal legislative sessions for the year are to conclude next Thursday.

Senators defended the vote on the controversial provision, which state gun rights advocates, including the local affiliate of the National Rifle Association, pressed hard to have removed.

“A lot of members felt that since the focus of that was on long guns, which is basically what people use for recreation and sport, there were sufficient controls through the federal criteria and therefore it was not necessary,” said Senator Stanley C. Rosenberg, an Amherst Democrat.

There was a glimmer of a potential compromise Tuesday evening: Six senators who voted to remove the provision offered new language in a letter to the conference committee.

But the dispute was clearly simmering earlier in the day.

Senate President Therese Murray initially declined to answer shouted questions from a reporter about the police chiefs’ concerns Tuesday afternoon. She later referred queries to the Senate chairman of the Joint Committee on Public Safety and Homeland Security, James E. Timilty.

Pressed for her personal opinion on the disputed provision as she entered a State House elevator, Murray declined to say.

Under current law, police chiefs must give people who pass a background check and meet other basic criteria a firearms identification card, which allows them to buy shotguns and rifles. But for handguns, police chiefs have discretion on whether to issue a license to carry and can deny one if they deem an applicant unsuitable. The disputed part of the bill would give chiefs the same discretion they currently have on issuing handgun licenses and apply it to rifles and shotguns.

Police chiefs say they and their officers know their communities and are well positioned to screen out potentially dangerous people from gaining access to shotguns and rifles.

The Senate legislation, said Evans, the Boston police commissioner, “doesn’t give us the ability to stop people from possessing rifles and shotguns . . . who aren’t suitable persons to have them, whether they have [been] involved in domestic violence incidents that we’re well aware of or they have some mental issues.”

In an e-mailed statement, Timilty expressed concern that the measure might violate the US Constitution.

He has said critics should look at the whole bill. Among other measures, it would have Massachusetts join a national database for criminal and mental health background checks, require schools to develop plans to address students’ mental health needs, and increase penalties for certain firearm crimes.

The Gun Owners’ Action League of Massachusetts, a local affiliate of the National Rifle Association, opposed the disputed provision giving police chiefs the added authority and pressed hard for its removal from the Senate bill.

Jim Wallace, GOAL’s executive director, told reporters Tuesday it would be problematic to expand police chiefs’ ability to decide who can get a gun because, he said, those powers have already been widely abused.

But Massachusetts Chiefs of Police Association president Erik Blake said at the press conference that the provision giving police added discretion on firearms identification cards is “not about being capricious or arbitrary or taking away people’s rights.”

Despite pressure from both gun control and gun rights advocates, there appeared to be a path to a compromise.

Tuesday evening, six senators who said they have supported gun control for years and were among the 28 senators voting to strip the disputed provision last week released a letter. They called the provision removed by the Senate “unacceptably vague” and offered language to give police chiefs authority to deny someone a firearms identification card using what they said was a narrower legal standard.

“We think it is a more targeted way of getting at what is a broadly shared goal,” said one of the senators, Benjamin B. Downing, Democrat of Pittsfield.

The early response from one gun control advocate was guardedly positive. “That’s much better than nothing,” said Rosenthal, the founder of Stop Handgun Violence.

A GOAL spokeswoman said Wallace was reviewing the language but is glad more voices are joining the conversation.

The Senate passed the amendment taking out the disputed provision by a vote of 28 to 10 Thursday. It subsequently passed the broader bill by a voice vote, which meant that individual lawmakers did not have to record where they stood on the legislation.

The press conference with the chiefs of police and advocates was organized on short notice by Stop Handgun Violence and the Massachusetts Coalition to Prevent Gun Violence.

Cunningham, the Wellesley police chief who is also a former president of the Massachusetts Chiefs of Police Association, said it was very rare to have police chiefs protest at the State House on such short notice. But, he added in a telephone interview, the rally came about because the disputed measure “is really important to us. It’s important to keep people safe.”

If a new anti-gun violence bill, crafted in response to the December 2012 Newtown, Conn., school massacre, becomes law, it will build on the state’s wide-ranging 1998 gun law, which has been called among the toughest in the nation.